The United States says it is not giving up on efforts to persuade Haitian opposition leaders to accept the international peace plan for the troubled country despite their stated rejection of the power-sharing arrangement Tuesday. The opposition said it could not accept the plan because it does not require Haitian President Jean-Bertrand Aristide to step down.

The Bush administration is not taking no for answer and says it will continue pressing for the settlement plan despite the decision by opposition leaders announced as a deadline expired Tuesday afternoon.

A State Department official said the Haitian parties must not miss the opportunity to resolve the crisis in a peaceful democratic manner, and that U.S. officials are still talking and working with the parties to gain acceptance for the plan.

The official said Secretary of State Colin Powell was personally involved in the effort, and spoke by telephone Tuesday with Haitian opposition leader Andre Arpaid and French Foreign Minister Dominique de Villepin.

She said the United States supports a French proposal to convene a meeting of the Haitian parties this week in Paris.

Under the plan by the United States, France, Canada and the Caribbean grouping CARICOM, Mr. Aristide would be allowed to serve out his current term running through February 2006, but would share power with a new prime minister and broad-based advisory council.

The unity government would lay groundwork for new parliamentary elections later this year that would end the political stalemate in the country stemming from disputed voting for years ago.

State Department spokesman Richard Boucher says it provides a way for the opposition to participate fully in the government.

"The plan that's been presented would created an independent prime minister and government that would run the country, create responsible police forces," he said. "It would create a fair opportunity for all the parties in Haiti to participate in a peaceful, democratic and constitutional process in Haiti, and that the parties need to seize this opportunity."

U.S. officials have said the sponsors are prepared to guarantee the implementation of the plan, and that its acceptance would be followed by the deployment of international police to help keep the peace.

The Bush administration has ruled out U.S. military intervention to quell the violence and has not said whether it would contribute to the promised police force.

The Haitian crisis, meanwhile, is drawing expressions of concern in the U.S. Congress including criticism from Democrats that the Bush administration has not been fully engaged in efforts to stem the violence.

Connecticut Senator Chris Dodd, senior Democrat on the Senate Foreign Relations Committee's Western Hemisphere Subcommittee, said the United States should "step up" and offer to send in armed forces if necessary to protect the elected Haitian government.

Florida Senator Bob Graham said he had detected little concern by the administration that the crisis might trigger an exodus of Haitian boat people to Florida and elsewhere in the region.

"If we continue to wait for a political solution, the country will be controlled by armed gangs, drug dealers and thugs," he said. "These conditions represent a clear threat to the national security of the United States of America and to the security of friendly allies even closer to Haiti than we are."

State Department spokesman Boucher said the administration is concerned about the prospect and is taking precautions, but has seen no indication of a impending mass migration of Haitians.

He said U.S. policy is clear, and that migrants would be intercepted and repatriated absent convincing evidence that individuals had a credible fear of persecution if sent back.